Beacon Power, LLC Response to the New York Energy Highway ...

There a several benefits of using flywheel storage for frequency regulation that align
with the Energy Highway Objectives:
1.
As a new, fast, accurate resource for maintaining grid frequency, flywheel energy
storage assures that long-term reliability of the electric system is cost-effectively
maintained, benefiting system performance and operations.
Beacon Power’s technology provides a fast response solution for maintaining grid
reliability. With a 25 kWh/100 kW flywheel system, Beacon’s technology can respond to an
ISO’s control signal up to one hundred times faster than what is offered by traditional
generators. Since fast regulation resources are significantly more effective at responding to
system imbalances than slower-ramping generation resources, their use on the grid can lower
the overall amount of Regulation that needs to be purchased to maintain system reliability.
The following example shows the greater effectiveness provided by using flywheel
energy storage for frequency regulation. On September 25, 2011, at hour ending 16, Beacon’s
flywheel regulation plant in Stephentown, NY supplied 20 MW of Regulation capacity to the
NYISO regulation market, or 11% of the total 175 MW of Regulation capacity procured during
the hour. 1 Based upon data provided by NYISO, during that hour the total Area Control Error
(“ACE”), which is a measurement of the frequency error and system imbalance on the grid, was
44.3 MWh (the sum of positive ACE MWh with the absolute value of negative ACE MWh). 2 In
this hour, Beacon’s 20 MW flywheel plant provided 14.2 MWh of energy to correct ACE or
32.2% of the total ACE Correction due its ability to respond in seconds to the error. For the
same hour, Beacon Power modeled a traditional generator supplying 20 MW of Regulation
capacity with the allowable 5-minute response time following NYISO’s pro-rated control signal
derived from ACE. Based on its models, the generator would be dispatched to provide 3.7
MWh of energy to correct ACE correction, or just 8.3% of the total ACE Correction needed. (See
Figure 1). The blue line is the actual amount of regulation service provided by Beacon Power’s
20 MW flywheel plant by responding every 6-seconds to the NYISO dispatch signal and the red
line shows the amount of regulation service provided by a 20 MW resource with a 5-minute
response time.
1 NYISO Regulation Requirements, http://www.nyiso.com/public/webdocs/market_data/reports_info/nyiso_regulation_req.pdf,
Accessed 9/26/11.
2 Area Control Error (“ACE”) is defined by NERC as “The instantaneous difference between a Balancing Authority’s net actual
and scheduled interchange, taking into account the effects of Frequency Bias and correction for meter error.” ACE data
provided by NYISO. System ACE data is telemetered to Stephentown plant in conjunction with the plant’s specific dispatch
signal.
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